Browse > Article
http://dx.doi.org/10.14773/cst.2021.20.4.175

A Study on the Corrosion Behavior of Magnesium Alloy Sealed with Chemical Conversion Coating and Sol-gel Coating  

Lee, Dong Uk (Department of Industrial Chemistry, Pukyong National University)
Chaudhari, Shivshankar (Department of Industrial Chemistry, Pukyong National University)
Choi, Seung Yong (Department of Industrial Chemistry, Pukyong National University)
Moon, Myung Jun (Department of Industrial Chemistry, Pukyong National University)
Shon, Min Young (Department of Industrial Chemistry, Pukyong National University)
Publication Information
Corrosion Science and Technology / v.20, no.4, 2021 , pp. 175-182 More about this Journal
Abstract
Magnesium alloy is limited in the industrial field because its standard electrode potential is -2.363 V vs. NHE (Normal Hydrogen Electrode) at 25 ℃. This high electrochemical activity causes magnesium to quickly corrode with oxygen in air; chemical conversion coating prevents corrosion but causes surface defects like cracks and pores. We have examined the anti-corrosion effect of sol-gel coating sealed on the defected conversion coating layer. Sol-gel coatings produced higher voltage current and smaller pore than the chemical conversion coating layer. The conversion coating on magnesium alloy AZ31 was prepared using phosphate-permanganate solution. The sol-gel coating was designed using trimethoxymethylsilane (MTMS) and (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) as precursors, and aluminum acetylacetonate as a ring-opening agent. The thermal shock resistance was tested by exposing specimens at 140 ℃ in a convection oven; the results showed changes in the magnesium alloy AZ31 surface, such as oxidization and cracking. Scanning electron microscope (FE-SEM) analysis confirmed a sealed sol-gel coating layer on magnesium alloy AZ31. Electrochemical impedance spectroscopy (EIS) measured the differences in corrosion protection properties by sol-gel and conversion coatings in 0.35 wt% NaCl solution, and the potentiodynamic polarization test and confirmed conversion coating with the sol-gel coating show significantly improved resistance by crack sealing.
Keywords
Sol-gel coating; EIS; Chemical conversion coating; Polarization test; Thermal shock test;
Citations & Related Records
연도 인용수 순위
  • Reference
1 H. Dong, Z. Jin, H. Jinfeng, L. Yong, and H. Guangyu, A review on ignition mechanisms and characteristics of magnesium alloys, Journal of Magnesium and Alloys, 8, 329 (2020). Doi: https://doi.org/10.1016/j.jma.2019.11.014   DOI
2 W. J. Joost and P. E. Krajewski, Towards magnesium alloys for high-volume automotive applications, Scripta Materialia, 128, 107 (2017). Doi: https://doi.org/10.1016/j.scriptamat.2016.07.035   DOI
3 W. Gan, C. Liu, and F. Lu, Study on surface modification and properties of the AZ91D magnesium alloy used for automobile engine, Journal of Materials Research and Technology, Available online 4 May (2020). Doi: http://doi.org/10.1016/j.jmrt.2020.03.084   DOI
4 G. Song and D. H. Stjohn, Corrosion of magnesium alloys in commercial engine coolants, Materials and Corrosion, 56, 15-23 (2005). Doi: https://doi.org/10.1002/maco.200403803   DOI
5 P. Zhou, B. Yu, Y. Hou, G. Duan, L. Yang, B. Zhang, T. Zhang, and F. Wang, Revisiting the cracking of chemical conversion coating on magnesium alloys, Corrosion Science, 178, 109069 (2021). Doi: https://doi.org/10.1016/j.corsci.2020.109069   DOI
6 D. Balgude and A. Sabnis, Sol-gel derived hybrid coatings as an environment friendly surface treatment for corrosion protection of metals and their alloys, Journal of Sol-Gel Science and Technology, 64, 124 (2012). Doi: https://doi.org/10.1007/s10971-012-2838-z   DOI
7 J. Mosa, N. C. Rosero-Navarro, and M. Aparicio, Active corrosion inhibition of mild steel by environmentally-friendly Ce-doped organic-inorganic sol-gel coatings, RSC Advances, 6, 39577 (2016). Doi: https://doi.org/10.1039/C5RA26094A   DOI
8 J. Hu, Q. Li, X. Zhong, L. Zhang, and B. Chen, Composite anticorrosion coatings for AZ91D magnesium alloy with molybdate conversion coating and silicon sol-gel coatings, Progress in Organic Coatings, 66, 199 (2009). Doi: https://doi.org/10.1016/j.porgcoat.2009.07.003   DOI
9 M. L. Zheludkevich, I. M. Salvado, and M. G. S. Ferreira, Sol-gel coatings for corrosion protection of metals, Journal of Materials Chemistry, 15, 5099 (2005). Doi: https://doi.org/10.1039/B419153F   DOI
10 M. Whelan, J. Cassidy, and B. Duffy, Sol-gel sealing characteristics for corrosion resistance of anodised aluminium, Surface and Coatings Technology, 235, 86 (2013). Doi: https://doi.org/10.1016/j.surfcoat.2013.07.018   DOI
11 F. Mansfeld, Tafel slopes and corrosion rates from polarization resistance measurements, Corrosion, 29, 397 (1973). Doi: https://doi.org/10.5006/0010-9312-29.10.397   DOI
12 S. Liao, B. Yu, X. Zhang, X. Lu, P. Zhou, C. Zhang, X. Chen, T. Zhang, and F. Wang, New design principles for the bath towards chromate-and crack-free conversion coatings on magnesium alloys, Journal of Magnesium and Alloys, 9, 505 (2021). Doi: https://doi.org/10.1016/j.jma.2019.12.013   DOI
13 M. Easton, A. Beer, M. Barnett, C. Davies, G. Dunlop, U. Durandet, S. Blacket, T. Hilditch, and P. Beggs, Magnesium alloy applications in automotive structures, JOM, 60, 57 (2008). Doi: https://doi.org/10.1007/s11837-008-0150-8   DOI
14 V. R. Capelossi, M. Poelman, I. Recloux, R. P. B. hernandez, J. G. de Melo, and M. G. Oliver, Corrosion protection of clad 2024 aluminum alloy anodized in tartaricsulfuric acid bath and protected with hybrid sol-gel coating, Electrochimica Acta, 124, 69 (20140). Doi: https://doi.org/10.1016/j.electacta.2013.09.004   DOI
15 R. Bandy, The simultaneous determination of tafel constants and corrosion rate-A new method, Corrosion Science, 20, 1017 (1980). Doi: https://doi.org/10.1016/0010-938X(80)90081-5   DOI